diff --git a/hal/api/critical.h b/hal/api/critical.h index 2c288a54301..df60f11f0fd 100644 --- a/hal/api/critical.h +++ b/hal/api/critical.h @@ -19,6 +19,8 @@ #define __MBED_UTIL_CRITICAL_H__ #include +#include +#include #ifdef __cplusplus extern "C" { @@ -47,7 +49,7 @@ bool core_util_are_interrupts_enabled(void); * section) will be preserved on exit from the section. * 4) This implementation will currently only work on code running in privileged mode. */ -void core_util_critical_section_enter(); +void core_util_critical_section_enter(void); /** Mark the end of a critical section * @@ -60,7 +62,7 @@ void core_util_critical_section_enter(); * section) will be preserved on exit from the section. * 4) This implementation will currently only work on code running in privileged mode. */ -void core_util_critical_section_exit(); +void core_util_critical_section_exit(void); /** * Atomic compare and set. It compares the contents of a memory location to a @@ -106,7 +108,7 @@ void core_util_critical_section_exit(); * * function incr(p : pointer to int, a : int) returns int { * done = false - * *value = *p // This fetch operation need not be atomic. + * value = *p // This fetch operation need not be atomic. * while not done { * done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success * } @@ -159,7 +161,7 @@ bool core_util_atomic_cas_u8(uint8_t *ptr, uint8_t *expectedCurrentValue, uint8_ * * function incr(p : pointer to int, a : int) returns int { * done = false - * *value = *p // This fetch operation need not be atomic. + * value = *p // This fetch operation need not be atomic. * while not done { * done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success * } @@ -212,7 +214,7 @@ bool core_util_atomic_cas_u16(uint16_t *ptr, uint16_t *expectedCurrentValue, uin * * function incr(p : pointer to int, a : int) returns int { * done = false - * *value = *p // This fetch operation need not be atomic. + * value = *p // This fetch operation need not be atomic. * while not done { * done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success * } @@ -221,13 +223,66 @@ bool core_util_atomic_cas_u16(uint16_t *ptr, uint16_t *expectedCurrentValue, uin */ bool core_util_atomic_cas_u32(uint32_t *ptr, uint32_t *expectedCurrentValue, uint32_t desiredValue); +/** + * Atomic compare and set. It compares the contents of a memory location to a + * given value and, only if they are the same, modifies the contents of that + * memory location to a given new value. This is done as a single atomic + * operation. The atomicity guarantees that the new value is calculated based on + * up-to-date information; if the value had been updated by another thread in + * the meantime, the write would fail due to a mismatched expectedCurrentValue. + * + * Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect + * you to the article on compare-and swap]. + * + * @param ptr The target memory location. + * @param[in,out] expectedCurrentValue A pointer to some location holding the + * expected current value of the data being set atomically. + * The computed 'desiredValue' should be a function of this current value. + * @Note: This is an in-out parameter. In the + * failure case of atomic_cas (where the + * destination isn't set), the pointee of expectedCurrentValue is + * updated with the current value. + * @param[in] desiredValue The new value computed based on '*expectedCurrentValue'. + * + * @return true if the memory location was atomically + * updated with the desired value (after verifying + * that it contained the expectedCurrentValue), + * false otherwise. In the failure case, + * exepctedCurrentValue is updated with the new + * value of the target memory location. + * + * pseudocode: + * function cas(p : pointer to int, old : pointer to int, new : int) returns bool { + * if *p != *old { + * *old = *p + * return false + * } + * *p = new + * return true + * } + * + * @Note: In the failure case (where the destination isn't set), the value + * pointed to by expectedCurrentValue is still updated with the current value. + * This property helps writing concise code for the following incr: + * + * function incr(p : pointer to int, a : int) returns int { + * done = false + * value = *p // This fetch operation need not be atomic. + * while not done { + * done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success + * } + * return value + a + * } + */ +bool core_util_atomic_cas_ptr(void **ptr, void **expectedCurrentValue, void *desiredValue); + /** * Atomic increment. * @param valuePtr Target memory location being incremented. * @param delta The amount being incremented. * @return The new incremented value. */ -uint8_t core_util_atomic_incr_u8(uint8_t * valuePtr, uint8_t delta); +uint8_t core_util_atomic_incr_u8(uint8_t *valuePtr, uint8_t delta); /** * Atomic increment. @@ -235,7 +290,7 @@ uint8_t core_util_atomic_incr_u8(uint8_t * valuePtr, uint8_t delta); * @param delta The amount being incremented. * @return The new incremented value. */ -uint16_t core_util_atomic_incr_u16(uint16_t * valuePtr, uint16_t delta); +uint16_t core_util_atomic_incr_u16(uint16_t *valuePtr, uint16_t delta); /** * Atomic increment. @@ -243,7 +298,18 @@ uint16_t core_util_atomic_incr_u16(uint16_t * valuePtr, uint16_t delta); * @param delta The amount being incremented. * @return The new incremented value. */ -uint32_t core_util_atomic_incr_u32(uint32_t * valuePtr, uint32_t delta); +uint32_t core_util_atomic_incr_u32(uint32_t *valuePtr, uint32_t delta); + +/** + * Atomic increment. + * @param valuePtr Target memory location being incremented. + * @param delta The amount being incremented in bytes. + * @return The new incremented value. + * + * @note The type of the pointer argument is not taken into account + * and the pointer is incremented by bytes. + */ +void *core_util_atomic_incr_ptr(void **valuePtr, ptrdiff_t delta); /** * Atomic decrement. @@ -251,7 +317,7 @@ uint32_t core_util_atomic_incr_u32(uint32_t * valuePtr, uint32_t delta); * @param delta The amount being decremented. * @return The new decremented value. */ -uint8_t core_util_atomic_decr_u8(uint8_t * valuePtr, uint8_t delta); +uint8_t core_util_atomic_decr_u8(uint8_t *valuePtr, uint8_t delta); /** * Atomic decrement. @@ -259,7 +325,7 @@ uint8_t core_util_atomic_decr_u8(uint8_t * valuePtr, uint8_t delta); * @param delta The amount being decremented. * @return The new decremented value. */ -uint16_t core_util_atomic_decr_u16(uint16_t * valuePtr, uint16_t delta); +uint16_t core_util_atomic_decr_u16(uint16_t *valuePtr, uint16_t delta); /** * Atomic decrement. @@ -267,7 +333,18 @@ uint16_t core_util_atomic_decr_u16(uint16_t * valuePtr, uint16_t delta); * @param delta The amount being decremented. * @return The new decremented value. */ -uint32_t core_util_atomic_decr_u32(uint32_t * valuePtr, uint32_t delta); +uint32_t core_util_atomic_decr_u32(uint32_t *valuePtr, uint32_t delta); + +/** + * Atomic decrement. + * @param valuePtr Target memory location being decremented. + * @param delta The amount being decremented in bytes. + * @return The new decremented value. + * + * @note The type of the pointer argument is not taken into account + * and the pointer is decremented by bytes + */ +void *core_util_atomic_decr_ptr(void **valuePtr, ptrdiff_t delta); #ifdef __cplusplus } // extern "C" diff --git a/hal/common/critical.c b/hal/common/critical.c index 47bfd23b128..f4ec8eb2f1d 100644 --- a/hal/common/critical.c +++ b/hal/common/critical.c @@ -15,15 +15,11 @@ * limitations under the License. */ -#define __STDC_LIMIT_MACROS -#include -#include +#include "critical.h" + #include "cmsis.h" #include "mbed_assert.h" -// Module include -#include "critical.h" - #define EXCLUSIVE_ACCESS (!defined (__CORTEX_M0) && !defined (__CORTEX_M0PLUS)) static volatile uint32_t interrupt_enable_counter = 0; @@ -38,7 +34,7 @@ bool core_util_are_interrupts_enabled(void) #endif } -void core_util_critical_section_enter() +void core_util_critical_section_enter(void) { bool interrupts_disabled = !core_util_are_interrupts_enabled(); __disable_irq(); @@ -63,7 +59,7 @@ void core_util_critical_section_enter() interrupt_enable_counter++; } -void core_util_critical_section_exit() +void core_util_critical_section_exit(void) { /* If critical_section_enter has not previously been called, do nothing */ if (interrupt_enable_counter) { @@ -127,7 +123,7 @@ bool core_util_atomic_cas_u32(uint32_t *ptr, uint32_t *expectedCurrentValue, uin return !__STREXW(desiredValue, (volatile uint32_t*)ptr); } -uint8_t core_util_atomic_incr_u8(uint8_t * valuePtr, uint8_t delta) +uint8_t core_util_atomic_incr_u8(uint8_t *valuePtr, uint8_t delta) { uint8_t newValue; do { @@ -136,7 +132,7 @@ uint8_t core_util_atomic_incr_u8(uint8_t * valuePtr, uint8_t delta) return newValue; } -uint16_t core_util_atomic_incr_u16(uint16_t * valuePtr, uint16_t delta) +uint16_t core_util_atomic_incr_u16(uint16_t *valuePtr, uint16_t delta) { uint16_t newValue; do { @@ -145,7 +141,7 @@ uint16_t core_util_atomic_incr_u16(uint16_t * valuePtr, uint16_t delta) return newValue; } -uint32_t core_util_atomic_incr_u32(uint32_t * valuePtr, uint32_t delta) +uint32_t core_util_atomic_incr_u32(uint32_t *valuePtr, uint32_t delta) { uint32_t newValue; do { @@ -155,7 +151,7 @@ uint32_t core_util_atomic_incr_u32(uint32_t * valuePtr, uint32_t delta) } -uint8_t core_util_atomic_decr_u8(uint8_t * valuePtr, uint8_t delta) +uint8_t core_util_atomic_decr_u8(uint8_t *valuePtr, uint8_t delta) { uint8_t newValue; do { @@ -164,7 +160,7 @@ uint8_t core_util_atomic_decr_u8(uint8_t * valuePtr, uint8_t delta) return newValue; } -uint16_t core_util_atomic_decr_u16(uint16_t * valuePtr, uint16_t delta) +uint16_t core_util_atomic_decr_u16(uint16_t *valuePtr, uint16_t delta) { uint16_t newValue; do { @@ -173,7 +169,7 @@ uint16_t core_util_atomic_decr_u16(uint16_t * valuePtr, uint16_t delta) return newValue; } -uint32_t core_util_atomic_decr_u32(uint32_t * valuePtr, uint32_t delta) +uint32_t core_util_atomic_decr_u32(uint32_t *valuePtr, uint32_t delta) { uint32_t newValue; do { @@ -236,7 +232,14 @@ bool core_util_atomic_cas_u32(uint32_t *ptr, uint32_t *expectedCurrentValue, uin return success; } -uint8_t core_util_atomic_incr_u8(uint8_t * valuePtr, uint8_t delta) +bool core_util_atomic_cas_ptr(void **ptr, void **expectedCurrentValue, void *desiredValue) { + return core_util_atomic_cas_u32( + (uintptr_t *)ptr, + (uintptr_t *)expectedCurrentValue, + (uintptr_t)desiredValue); +} + +uint8_t core_util_atomic_incr_u8(uint8_t *valuePtr, uint8_t delta) { uint8_t newValue; core_util_critical_section_enter(); @@ -246,7 +249,7 @@ uint8_t core_util_atomic_incr_u8(uint8_t * valuePtr, uint8_t delta) return newValue; } -uint16_t core_util_atomic_incr_u16(uint16_t * valuePtr, uint16_t delta) +uint16_t core_util_atomic_incr_u16(uint16_t *valuePtr, uint16_t delta) { uint16_t newValue; core_util_critical_section_enter(); @@ -256,7 +259,7 @@ uint16_t core_util_atomic_incr_u16(uint16_t * valuePtr, uint16_t delta) return newValue; } -uint32_t core_util_atomic_incr_u32(uint32_t * valuePtr, uint32_t delta) +uint32_t core_util_atomic_incr_u32(uint32_t *valuePtr, uint32_t delta) { uint32_t newValue; core_util_critical_section_enter(); @@ -266,8 +269,12 @@ uint32_t core_util_atomic_incr_u32(uint32_t * valuePtr, uint32_t delta) return newValue; } +void *core_util_atomic_incr_ptr(void **valuePtr, ptrdiff_t delta) { + return core_util_atomic_incr((uintptr_t)valuePtr, (uintptr_t)delta); +} + -uint8_t core_util_atomic_decr_u8(uint8_t * valuePtr, uint8_t delta) +uint8_t core_util_atomic_decr_u8(uint8_t *valuePtr, uint8_t delta) { uint8_t newValue; core_util_critical_section_enter(); @@ -277,7 +284,7 @@ uint8_t core_util_atomic_decr_u8(uint8_t * valuePtr, uint8_t delta) return newValue; } -uint16_t core_util_atomic_decr_u16(uint16_t * valuePtr, uint16_t delta) +uint16_t core_util_atomic_decr_u16(uint16_t *valuePtr, uint16_t delta) { uint16_t newValue; core_util_critical_section_enter(); @@ -287,7 +294,7 @@ uint16_t core_util_atomic_decr_u16(uint16_t * valuePtr, uint16_t delta) return newValue; } -uint32_t core_util_atomic_decr_u32(uint32_t * valuePtr, uint32_t delta) +uint32_t core_util_atomic_decr_u32(uint32_t *valuePtr, uint32_t delta) { uint32_t newValue; core_util_critical_section_enter(); @@ -297,5 +304,9 @@ uint32_t core_util_atomic_decr_u32(uint32_t * valuePtr, uint32_t delta) return newValue; } +void *core_util_atomic_decr_ptr(void **valuePtr, ptrdiff_t delta) { + return core_util_atomic_decr((uintptr_t)valuePtr, (uintptr_t)delta); +} + #endif